(Arch) Linux build on master broken: rapidjson/document.h missing

[robindegen]

System Information

• Ogre Version: current master (ede1690bb3dcf932df6a06f06e9e6de585e5eeea)
• Operating System / Platform: Arch Linux
• RenderSystem: Any
• GPU: Nvidia

Detailled description

Trying to build master out of the box fails with a missing rapidjson/document.h inclusion. It is not mentioned as a dependency in the readme, nor does CMake actually require rapidjson to be installed. Manually installing the library fixes the problem; but CMake should fail on not finding this, or the inclusion should be optional based on if the library is available, or the readme should be modified to include the library.

[1/598] Building CXX object OgreMain/CMakeFiles/OgreMain.dir/src/OgreRootLayout.cpp.o
FAILED: OgreMain/CMakeFiles/OgreMain.dir/src/OgreRootLayout.cpp.o 
/usr/bin/c++ -DFREEIMAGE_LIB -DOGRE_NONCLIENT_BUILD -DOgreMain_EXPORTS -D_MT -D_USRDLL -I/home/robindegen/development/external/ogre-next/OgreMain/include -I/home/robindegen/development/external/ogre-next/build/include -I/usr/include/freetype2 -I/home/robindegen/development/external/ogre-next -I/home/robindegen/development/external/ogre-next/OgreMain/include/Threading -I/home/robindegen/development/external/ogre-next/OgreMain/include/GLX -Wall -Winit-self -Wcast-qual -Wwrite-strings -Wextra -Wno-unused-parameter -Wshadow -Wimplicit-fallthrough -Wsuggest-override -Wno-unused-but-set-parameter  -msse -msse2 -O2 -g -DNDEBUG -fPIC   -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -MD -MT OgreMain/CMakeFiles/OgreMain.dir/src/OgreRootLayout.cpp.o -MF OgreMain/CMakeFiles/OgreMain.dir/src/OgreRootLayout.cpp.o.d -o OgreMain/CMakeFiles/OgreMain.dir/src/OgreRootLayout.cpp.o -c /home/robindegen/development/external/ogre-next/OgreMain/src/OgreRootLayout.cpp
/home/robindegen/development/external/ogre-next/OgreMain/src/OgreRootLayout.cpp:48:10: fatal error: rapidjson/document.h: No such file or directory
   48 | #include "rapidjson/document.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~
compilation terminated.